1. Field of the Invention
The present invention generally relates to judgment methods, and more particularly to a method for detecting. when an image-forming device is inspected for maintenance purposes, deterioration in each device component. The method of the present invention is suitable, for example, for maintenance inspection of an electrophotographic printing device, such as a copier.
2. Description of the Related Art
A conventional maintenance inspection for an electrophotographic printer has required a maintenance man to use a manual operation and consider each component to be normal if it is currently working, except for components that may be inspected with eyes such as toner in a transparent plastic vessel. A maintenance man would consider a component to be abnormal and exchange/repair it only when it is completely inoperable or very hard to operate. In other words, the conventional maintenance inspection has only judged whether a target component is normal or abnormal, and considered the component to be normal if judging it not to be abnormal.
The conventional maintenance inspection cannot help considering a component to be normal which is not completely normal but it has not reached the apparently abnormal state (referred to as xe2x80x9ca deteriorated statexe2x80x9d hereinafter). However, the subsequent continuous use of the deteriorated state is likely to bring about a near-future failure or very bad operation. Therefore, the conventional maintenance inspection would often result in inoperativeness shortly after the maintenance inspection, annoying customers. In addition, it has been disadvantageously difficult for the conventional maintenance inspection to easily judge whether a component is in the deteriorated state.
The deterioration in a printer component may disable printing in the near future as well as gradually lower the print quality. A print operation depends upon components having various print functions as a whole. One deteriorated component would possibly lower the entire print quality. However, the conventional maintenance inspection has a difficulty in quantitatively evaluating the print quality. Even a detection of the image-quality deterioration cannot easily trace the causative component.
Therefore, it is an exemplified general object of the present invention to provide a novel and useful evaluation method and printer in which the above disadvantages are eliminated.
Another exemplified and more specific object of the present invention is to provide an evaluation method and printer without additional complex detecting means that may enable a maintenance mall to easily identify a deteriorated component in addition to a component that is broken down or is remarkably hard to operate.
Still another exemplified object of the present invention is to provide an evaluation method and printer that enable a maintenance man to quantitatively evaluate the current print quality.
Another exemplified object of the present invention is to provide a judgment method and printer that may easily localize a causative component after the image quality is considered deteriorated.
In order to achieve the above objects, a printer of a first aspect of the present invention comprises a mechanical part which feeds a printing paper and in order to print predetermined information on the printing paper, a mode switch which switches plural modes, and a control part which controls the mechanical part and determines quantitatively in each mode which state among normal, deteriorated, and abnormal states each component in said mechanical part is located in.
A printer of a second aspect of the present invention comprises a photosensitive body, a pre-charger which charges the photosensitive body, an optical part which exposes the charged photosensitive body, a developer which applies a bias voltage to toner and develops the exposed photosensitive body, forming a toner image with a desired concentration, a transfer unit which transfers the toner image onto a printing paper by applying a transfer current to the printing paper, and a control part which enable printing by setting to a printable upper and lower limits one or more set values among electric parameters including a surface potential in the photosensitive body, an exposure power in the optical part, the bias voltage in the developer, and the transfer current in the transfer unit.
An evaluation method of the present invention comprises the steps of setting a mode used to test a print quality margin, setting to an upper or lower value one or more set values among electric parameters including a surface potential in said photosensitive body, an exposure power in the optical part, a bias voltage in the developer, and a transfer current in the transfer unit, printing a predetermined pattern in accordance with the set electric parameters.
Other objects and further features of the present invention will become readily apparent from the following description of the embodiments with reference to accompanying drawings.